The invention relates to a motor vehicle, in particular a motorcycle or a vehicle similar to a motorcycle, having a vehicle suspension which is damped by means of a spring arrangement.
From the prior art, motorcycles are known with a height-adjustable chassis and enable an adjustment of the vehicle height using adjustable suspension struts, for example, for adapting to different vehicle states.
There is known, for example, under the name “Electronic Suspension Adjustment” (ESA) and “Dynamic ESA” an electronic chassis from the same Applicant. The adjustability affords the driver improvements with respect to road safety and performance. The damping of the suspension struts is in this instance adapted to the front wheel and rear wheel by means of electrically controlled adjustment valves in order to achieve a significantly improved contact between the road and tires. A lowering or raising of the travel position is carried out in this instance by means of corresponding adjustment of a respective spring base.
Furthermore, adjustment devices with adjustable telescope-like spring forks are known, such as, for example, from WO 2013/066159 A1. In contrast, a possible variant of an active rear wheel suspension is described in EP 1 197 361 B1.
In order, however, to achieve a very rapid adjustment of the chassis height, in particular raising from a lowered position back into a normal or raised travel position, with the known adjustment devices high levels of power are required in order to adjust the suspension struts counter to the gravitational force of the vehicle. In addition, the adjustment devices are partially structurally and functionally integrated in other vehicle components.
An object of the invention is therefore to provide a height adjustment for a vehicle, in particular a motorcycle or a vehicle similar to a motorcycle, which enables a rapid and easy adjustment and which additionally can be provided where possible independently of other vehicle components in the vehicle.
Accordingly, a motor vehicle is provided, in particular a motorcycle or a vehicle similar to a motorcycle, having a wheel suspension which is damped by means of a spring arrangement and which is constructed for compression in a compression direction and extension in an opposing extension direction. Furthermore, there is provided a lowering device which can be selectively actuated by means of a pressure fluid and which is constructed in an active state to act on the wheel suspension with a preload which is directed in the compression direction.
If the driver thus wishes to lower the vehicle height, he can actuate the lowering device which can be actuated in a selective manner. In the active state thereof, the wheel suspension is acted on with a force, the preload. This force is directed in the compression direction of the wheel suspension and results in the damped wheel suspension being compressed in the compression direction by a compression path which corresponds to the preload. The preload thus acts counter to the extension direction of the spring arrangement of the wheel suspension so that accordingly the spring arrangement is compressed by the preload and consequently shortened. This leads to a lowering of the vehicle and a corresponding height adjustment.
Expressed in other words, as a result of the preload a compression movement is forced through a defined compression path and a corresponding extension is reduced by the lowering device and the action as long as the lowering device is active. In the active state, the wheel suspension is pressed by the preload provided by the lowering device “into the suspension” of the wheel suspension and retained at that location in the pretensioned state in a balance of forces between preload and an opposingly directed extension force of the spring arrangement.
The lowering device provided is preferably constructed so as to be able to be operated separately and independently from the spring arrangement and introduces the preload directly into the wheel suspension. To this end, the lowering device is preferably directly connected to the wheel suspension. This arrangement affords the advantage that in principle no change or adaptation of the conventional components of a wheel suspension are required. Instead, the lowering device can be provided in addition to the existing components, in particular to the damped wheel suspension. For example, the lowering device may be constructed in a modular manner and may thus be able to be integrated or replaced in existing vehicles.
Preferably, the lowering device has for the actuation thereof an individual pressure fluid supply. A coupling to other pressure fluid circuits of the vehicle is possible, but preferably not necessary.
In any case, as a result of the operating principle via the action of the preload on the wheel suspension, a lowering of the vehicle height can be carried out in a very simple and rapid manner. The same applies in reverse for the return to the normal non-lowered vehicle height. This is achieved by a deactivation of the lowering device in which the action of the preload on the wheel suspension is removed again.
As soon as the action of the lowering device on the wheel suspension is removed (in the inactive state), the restoring forces of the separate spring arrangement act in an unlimited manner so that the vehicle extends simply as a result of the extension force resulting from the compression path and the original vehicle height can be adjusted directly and immediately.
A vehicle similar to a motorcycle is intended to be understood to be in particular all two-wheeled vehicles but also multi-wheel vehicles each having a corresponding saddle-like bench type seat for the user, in a particularly preferred manner, two-wheel, three-wheel or four-wheel motor scooters or scooters.
The pressure fluid is a pressurized fluid or a pressurized gas which is placed under excess pressure with respect to ambient pressure. Accordingly, different variants of the lowering device are possible, a hydraulic or a pneumatic or a combined embodiment of these two variants.
According to an embodiment, the lowering device which can be selectively actuated by means of a pressure fluid may comprise a hydraulically actuatable adjustment element, in particular a hydraulic cylinder. By supplying the pressurized fluid (pressure fluid for short), the adjustment element can accordingly be actuated and a resulting adjustment force which can act on the wheel suspension as a preload can be provided. In order to further enable the wheel suspension to damp, compress and extend, the hydraulic cylinder may further be resiliently connected to a vehicle frame or has a resiliently constructed piston rod.
Alternatively or additionally, the lowering device which can be selectively actuated by means of a pressure fluid may comprise an adjustment element which can be actuated pneumatically, in particular a pneumatic cylinder. By supplying the gaseous, pressurized fluid (pressure fluid for short), the adjustment element can be accordingly actuated and a resulting adjustment force which can act on the wheel suspension as a preload can be provided.
Furthermore, the damped wheel suspension may be constructed as a front wheel suspension for at least one front wheel, having an upper suspension portion and a lower suspension portion which can be moved relative thereto, wherein the spring arrangement comprises at least one spring damper element, which is connected with a first end to the lower suspension portion and with an opposing second end to the upper suspension portion in order to resiliently support the lower suspension portion on the upper suspension portion.
For example, such front wheel suspensions have a single suspension strut or a suspension fork having two suspension struts. In each case, a portion associated with the front wheel, the lower suspension portion, can be moved in a relative manner and is arranged by means of the spring damper element in a state damped with respect to the upper suspension portion.
For example, the adjustment element may be connected with a first end to the upper suspension portion and with a second end to the lower suspension portion in order to selectively act on the damped front wheel suspension with the preload. As a result of the arrangement, the adjustment element counteracts in the active state the movement of the spring damper element at least with respect to an extension movement and limits the extent of the movement thereof. For example, the adjustment element is connected with the first end to a fork bridge, in particular a lower fork bridge (as an upper suspension portion) and with the second end to a sliding tube bridge or an insertion tube bridge (as a lower suspension portion).
Alternatively or additionally, the damped wheel suspension may be constructed as a rear wheel suspension for at least one rear wheel and may comprise a rear wheel rocker arm which is connected to a vehicle frame so as to be able to be rotated about a first rotation axis, wherein the spring arrangement comprises at least one spring damper element which is connected with a first end to the rear wheel rocker arm and with an opposing second end to the vehicle frame to resiliently support the rear wheel rocker arm.
The at least one spring damper element represents, for example, the spring arrangement of the rear wheel rocker arm provided for regular travel operation. The connection of the second end of the respective spring damper element can be carried out either directly and without any intermediate member with the vehicle frame, or indirectly by means of one or more interposed connection element(s) which can themselves be connected directly or indirectly to the vehicle frame.
For example, the adjustment element can be connected with a first end to the vehicle frame and with a second end to the rear wheel rocker arm in order to selectively act on the rear wheel rocker arm with the preload.
At least in the active state, there is consequently preferably produced a support of the lowering device, on the one hand, on the vehicle frame and, on the other hand, on the wheel suspension, in the case of both a front wheel suspension and a rear wheel suspension. In this manner, an adjustment force produced by the adjustment element is used to provide the preload on the wheel suspension by being directed in the compression direction and consequently counter to a resilient force or counter to an extension movement of the separate spring arrangement. In the case of a pneumatic adjustment element, the resilient action is maintained as a result of the compressibility of the fluid. To this end, however, in the case of a hydraulic adjustment element, a connection to the vehicle frame or the piston rod of the adjustment element can be constructed in a resilient manner.
Furthermore, the adjustment element may be positioned below a rotation axis of the rear wheel suspension so that the preload which is directed in the compression direction is provided by a pressure force which is applied by the adjustment element. Alternatively, the adjustment element may be positioned above the rear wheel rocker arm so that the preload which is directed in a compression direction is provided by means of a tensile force which is applied by the adjustment element.
Of course, the vehicle may comprise not only a lowering device on an individual wheel suspension which is constructed either as a front wheel suspension or as a rear wheel suspension. Instead, the vehicle may have both an individual lowering device for a front wheel suspension and an individual lowering device for the rear wheel suspension, which is constructed in any case in accordance with the description.
Independently of a use for a front wheel suspension and/or a rear wheel suspension, the lowering device provided affords particular advantages. The adjustment element carries out as a result of the individual action of the pressure fluid an action on the wheel suspension which acts counter to the spring arrangement so that the damped wheel suspension is moved in the compression direction. In this manner, the vehicle is lowered or a vehicle height is reduced and the vehicle is retained in this position as long as the adjustment element is active. To this end, the adjustment element limits in this position a movement extent of the wheel suspension in the opposite direction, that is to say, an extension in the extension direction. This means that, although the wheel suspension can be compressed further, it cannot extend beyond a maximum extension position which is limited by the adjustment element and the preload. In the case of a pneumatic adjustment element, the resilient action is maintained as a result of the compressibility of the fluid. To this end, however, in the case of a hydraulic adjustment element, a connection to the vehicle frame or the piston rod of the adjustment element can be constructed in a resilient manner.
In other words, the adjustment element represents a defined, adjustable resilient stop for the wheel suspension so that the maximum extension path is limited. The adjustment element may either be adjustable in a single position or one of several defined positions, gradually or steplessly, in order to accordingly adjust and vary the maximum extension path.
Also independently of a use of the lowering device for a front wheel suspension and/or a rear wheel suspension, the lowering device may according to one embodiment comprise a compressor and/or volume store which is connected to the adjustment element in a fluid-conveying manner for actuating the adjustment element by means of the pressure fluid. This means that the pressure fluid is placed under pressure by the compressor and is supplied to the adjustment element. As a result of the application of pressure to the adjustment element, it is actuated and—depending on the embodiment—lengthened or shortened. Accordingly, the pressure or tensile force produced brings about the preload on the connected wheel suspension. As an alternative to the compressor, the volume store may be provided, from which only a portion of the pressure fluid can also be supplied to the adjustment element or removed from the adjustment element.
According to a preferred embodiment, the lowering device has a valve which is constructed in an inactive state of the lowering device for connection of a first fluid chamber to a second fluid chamber of the adjustment element in a fluid-conveying manner and/or for at least partially discharging the pressure fluid from the adjustment element into a pressure-free reservoir or into an environment.
This means that the adjustment element in the non-inactive state can be deactivated using the valve by the valve producing a fluid-conveying connection between a first fluid chamber and a second fluid chamber. In this manner, the adjustment element is “short-circuited” so that the piston rod can be moved in an (almost) resistance-free manner in the adjustment element. Depending on the movement direction, the fluid can consequently be urged in one of the two fluid chambers and supplied via the valve to the other fluid chamber in each case. Only a flow resistance in the fluid line brings about a small, negligible movement resistance for the adjustment element.
Additionally or alternatively, the adjustment element may be “ventilated” and consequently switched into a pressure-free state by at least a partial discharge of the pressure fluid from the adjustment element into an environment in the inactive state of the lowering device being enabled. To this end, the valve may produce a connection to the environment in order to discharge excess fluid. This is particularly advantageous when redirecting from one pressure chamber into the other when the volume of the receiving pressure chamber is reduced as a result of a piston rod compared with the other pressure chamber. The connection to the environment may, for example, be carried out purely optionally by means of an auxiliary element in the form of a silencer, an air filter or an air dryer.
In both cases, although in this manner the adjustment element is also moved passively during a compression movement or extension movement of the wheel suspension, no counter-force is produced or the spring excursion influenced. Instead, the respective wheel suspension acts in an uninfluenced manner. This embodiment is—however, in a completely non-limiting manner—suitable in particular for the use of a gaseous pressure fluid, that is to say, in the case of the pneumatic adjustment element.
In any case, the embodiments of the lowering device provided have an advantageous effect on a lowering desired by the driver or restoring of the vehicle height to the original, non-lowered level. In this instance, the “resilient stop” formed by the adjustment element can be readily removed. Accordingly, the vehicle as a result of the spring arrangement can extend rapidly without additionally required auxiliary means.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.